F Pashaei Sorbaghi - PhD student
M Kokabi - Professor
O Rastegar - Graduate student
M Razzaghi Kashani - Associate Professor, Polymer Engineering

This paper deals with the effects of organoclay on the improvement of mechanical properties of polymer modified bitumen. Nanocomposites based on polypropylene (PP)/organoclay were first prepared by melt compounding. Ethylene vinyl acetate (EVA) was used as compatibilizer. The values of organically modified montmorillonite (OMMT) were 1 and 3 wt%. The ratio of Nanocomposite to bitumen in prepared blends was 45 /55 wt%. The X-ray diffraction (XRD) was used to characterize the morphology of nanocomposites. The mechanical properties of blends such as Young’s modulus and tensile strength were evaluated using tensile testing method. The XRD results showed the exfoliated morphology for nanocomposites which was remained unchanged after blending with bitumen. According to tensile test results, the values of Young’s modulus and tensile strength increased by increasing the organoclay loading level. The sample containing 3wt% of organoclay exhibited the maximum mechanical properties. This sample also indicated 33% and 10% improvement in Young’s modulus and tensile strength, in compare to organoclay-free sample, respectively. These improvements are attributed to better dispersion of polymer and bitumen phases in each other due to presence of organoclay. In fact organoclay causes better compatibility between two phases.

Nanocomposite; modified bitumen; blend; polypropylene; organoclay